oh yeah, i know (& finished) doki doki panic & super mario bros 2 usa - i was looking for the original NES version of Super Mario: The lost levels thats on super mario bros allstars - i heard it was called SMB2 in japan, but that rom you listed above is the same as the usa version

The disk system was an add-on for the Famicom. Instead of cardridges it had disk, sort of like in your PC.Several games were made for it including: Kid Icarus, Legend of Zelda2 and Super Mario 2They do pop up on ebay once in a while. I love to have one but they're f**king expensive...